Technical Paper
An Evaluation of Cosmetic Corrosion Performance of Zinc and Zinc Alloy Coated Steels
1986-12-08
862014
A comparison of the cosmetic corrosion performance of zinc and zinc-iron alloy coated steels is made. Cosmetic corrosion can be defined in terms of paint creepage/blistering, red rust, and paint adhesion. Traditional scribe-type tests adequately address creepage and rusting, but do not adequately address paint adhesion. A new lab procedure called the Chipping Corrosion Test was used to assess paint adhesion of coated steels processed under various phosphate conditions. A review of the relative performance of zinc and zinc alloy coated steels in traditional scribed panel corrosion tests and the new chipping corrosion lab procedure is presented. Results of the Chipping Corrosion Tests showed significant differences in material performance when processed under plant conditions that were not evident under laboratory process conditions, or in traditional scribe-type tests.